Multi-position Dimensional Synthesis of a Spatial 3-RPS Parallel Manipulator

2005 ◽  
Vol 128 (4) ◽  
pp. 815-819 ◽  
Author(s):  
Nalluri Mohan Rao ◽  
K. Mallikarjuna Rao

This paper presents dimensional synthesis of a 3 degrees of freedom (DOF) spatial 3-revolute-prismatic-spherical (RPS) parallel manipulator. Tsai and Kim ((2003) ASME J. Mech. Des., 125, pp. 92–97) have shown that the dimensional synthesis can be carried out for at the most six prescribed positions and orientations of the moving platform. The method of synthesis is modified (least-square technique) to make it possible to synthesize the 3-RPS manipulator for any number of positions and orientations of the moving platform. The effectiveness of the modified method of synthesis is demonstrated by considering an example for ten-position synthesis. The modified method of synthesis is an approximation method.

2003 ◽  
Vol 125 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Han Sung Kim ◽  
Lung-Wen Tsai

This paper presents the design of spatial 3-RPS parallel manipulators from dimensional synthesis point of view. Since a spatial 3-RPS manipulator has only 3 degrees of freedom, its end effector cannot be positioned arbitrarily in space. It is shown that at most six positions and orientations of the moving platform can be prescribed at will and, given six prescribed positions, there are at most ten RPS chains that can be used to construct up to 120 manipulators. Further, solution methods for fewer than six prescribed positions are also described.


2013 ◽  
Vol 330 ◽  
pp. 639-643 ◽  
Author(s):  
Chung Huang Yu ◽  
Wen Yeuan Chung

This paper proposed a new manipulator design concept which leads to a single DOF system. The system composed of a moving platform and several supporting legs. It can execute the tasks of 3D body guidance or path generation and thus replace expensive manipulators with high DOF in some conditions. There are mainly two steps in designing this manipulator. The first step is type synthesis to determine the number and types of legs. Dimensional synthesis is then executed based on the movement requirements and geometrical constraints. In this study the reduction of the DOF is also analyzed for various legs added between the moving platform and the ground. A numerical example of executing 3D body guidance is given to verify the proposed new concept.


Author(s):  
Richard Stamper ◽  
Lung-Wen Tsai

Abstract The dynamics of a parallel manipulator with three translational degrees of freedom are considered. Two models are developed to characterize the dynamics of the manipulator. The first is a traditional Lagrangian based model, and is presented to provide a basis of comparison for the second approach. The second model is based on a simplified Newton-Euler formulation. This method takes advantage of the kinematic structure of this type of parallel manipulator that allows the actuators to be mounted directly on the base. Accordingly, the dynamics of the manipulator is dominated by the mass of the moving platform, end-effector, and payload rather than the mass of the actuators. This paper suggests a new method to approach the dynamics of parallel manipulators that takes advantage of this characteristic. Using this method the forces that define the motion of moving platform are mapped to the actuators using the Jacobian matrix, allowing a simplified Newton-Euler approach to be applied. This second method offers the advantage of characterizing the dynamics of the manipulator nearly as well as the Lagrangian approach while being less computationally intensive. A numerical example is presented to illustrate the close agreement between the two models.


Robotica ◽  
2012 ◽  
Vol 31 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Jaime Gallardo-Alvarado ◽  
Mario A. García-Murillo ◽  
Eduardo Castillo-Castaneda

SUMMARYThis study addresses the kinematics of a six-degrees-of-freedom parallel manipulator whose moving platform is a regular triangular prism. The moving and fixed platforms are connected to each other by means of two identical parallel manipulators. Simple forward kinematics and reduced singular regions are the main benefits offered by the proposed parallel manipulator. The Input–Output equations of velocity and acceleration are systematically obtained by resorting to reciprocal-screw theory. A case study, which is verified with the aid of commercially available software, is included with the purpose to exemplify the application of the method of kinematic analysis.


Author(s):  
Ahmet Agaoglu ◽  
Namik Ciblak ◽  
Koray K. Safak

This work addresses the optimization of the workspace of a six degrees of freedom parallel manipulator. In this study, The topology of the manipulator is composed of three xy-tables, symmetrically positioned on a circle on a base plane, connected by three legs to a moving platform. Kinematic composition of the manipulator is introduced and kinematic diagram is illustrated. Orientation workspace is investigated using three different orientation representations. XYZ fixed angles representation is selected considering the benefits of its visualization are considered. By using this representation, the orientation workspace is modeled and kinematic circuits of the manipulator are explored. First, optimization is performed without slider limitations. A result table is obtained based on the user defined parameters. Secondly, optimization is performed under slider limitations. The maximal orientation capability is optimized using numerical analysis. The optimized configuration of the manipulator indicates that a 330% increase in orientation capability is achieved, compared to the old configuration.


2011 ◽  
Vol 201-203 ◽  
pp. 1849-1853
Author(s):  
Jing Li Yu ◽  
Gang Cheng ◽  
Shuai Zhang ◽  
De Kun Zhang

For a novel 3SPS+1PS parallel manipulator with 4 degrees of freedom including three rotations and one translation, the formulae for solving the inverse kinematics equations are derived based on quaternion method. Unit quaternion is used to represent the position and orientation of moving platform, and the singularities caused by Euler angles are avoided. Combining the topological structure characteristics of the parallel manipulator, it only has three rotations when its moving platform is at a given translation position. Based on the inverse position/pose equations and the all the constraints of the parallel manipulator, the discrete algorithm for the orientation workspaces of 3SPS+1PS parallel manipulator where the moving platform is at some different given translation positions are designed. The research builds the theoretical basis for optimizing the orientation workspace with given position.


Robotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 99
Author(s):  
Zhumadil Baigunchekov ◽  
Med Amine Laribi ◽  
Azamat Mustafa ◽  
Abzal Kassinov

In this paper, methods of kinematic synthesis and analysis of the RoboMech class parallel manipulator (PM) with two grippers (end effectors) are presented. This PM is formed by connecting two output objects (grippers) with a base using two passive and one negative closing kinematic chains (CKCs). A PM with two end effectors can be used for reloading operations of stamped products between two adjacent main technologies in a cold stamping line. Passive CKCs represent two serial manipulators with two degrees of freedom, and negative CKC is a three-joined link with three negative degrees of freedom. A negative CKC imposes three geometric constraints on the movements of the two output objects. Geometric parameters of the negative CKC are determined on the basis of the problems of the Chebyshev and least-square approximations. Problems of positions and analogues of velocities and accelerations of the PM with two end effectors have been solved.


Author(s):  
Benjamin Maurin ◽  
Bernard Bayle ◽  
Jacques Gangloff ◽  
Michel de Mathelin ◽  
Olivier Piccin

In this paper, a new five-degree-of-freedom parallel manipulator is described and modeled. This structure has been specially designed for medical applications that require in the same time mobility, compactness and accuracy around a functional point. The purpose of this robotic device is to help practitioners to perform accurate needle insertions while preserving them from harmful intra-operative X-ray imaging devices. The system is built from revolute joints, among which only five joints are actuated to convey the required five degrees of freedom to its moving platform. A numerical simulation of the workspace and a physical prototype are presented.


Author(s):  
Chunxu Tian ◽  
Dan Zhang ◽  
Jian Liu

A conventional parallel manipulator is characterized by connecting one moving platform with two or more serial kinematic limbs. Since each limb is independently supporting one moving platform, the moving platform must be a rigid body with several kinematic pairs fixed on it. However, for generalized parallel manipulators with articulated moving platforms, the moving platforms are not limited to rigid bodies but including serial kinematic chains or internal kinematic joints. The introduction of articulated moving platforms allows for improving the kinematic performance of generalized parallel manipulators, especially for rotational capability. On account of the structural characteristics of the moving platforms, it also poses a significant challenge in the construction of the structures of manipulators. This research raises a new method for the type synthesis of generalized parallel manipulators with novel articulated moving platforms. The proposed method introduces a striking shortcut for the limb structure analysis of mechanisms with high rotational capability. In this paper, a class of generalized parallel manipulator with different degrees of freedom from 3 to 6 are constructed by using the constraint synthesis method, and several examples are provided to demonstrate the feasibility of the advocated method. At last, the 3T3R generalized parallel manipulator is taken as an example to analyze the inverse kinematics, and the evaluation of the workspace is conducted to verify the rotational capacity.


2012 ◽  
Vol 162 ◽  
pp. 224-233 ◽  
Author(s):  
Mario Acevedo ◽  
Marco Ceccarelli ◽  
Giuseppe Carbone

The dynamic balancing of a spatial parallel manipulator of three degrees-of-freedom, CaPaMan-2 (Cassino Parallel Manipulator 2), by the application of Counter-Rotary Counterweights (CRCW) is analyzed. To accomplish this objective the mass and inertia of the moving platform are dynamically replaced by point masses located at the points of attachment of the legs to the platform and the mechanism is balanced by considering each of the legs independently. This fully parallel manipulator has three identical legs, each one composed by a four-bar mechanism (an articulated parallelogram) connected to the fixed base, and a link supported by the coupler that connects to the mobile platform. This link, seen as a pendulum, is transformed to a dynamic balancer using a Counter-Rotary Counterweight in order to compensate the motion of the moving platform. In a second stage the articulated parallelogram is modified by adding Counter-Rotary Counterweight plus a Counterweight to dynamic balance its part of the system. As a final result it is obtained a new design, with a parallel manipulator dynamic balanced. The resulting model of the manipulator is validated by dynamic simulation, using general purpose software for the analysis and dynamic simulation of multi-body systems (ADAMS).


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